A comparison of performance and emissions characteristics of an engine fuelled on DME and on diesel with particular interest on injection characteristics

摘要

This report contains the results of tests conducted on a compression ignition engineudwhich was fuelled on both DME and diesel. The results compare the performance andudemissions characteristics of the two fuels. As an addition to the existing test cell setup,udan injector lift sensor was added in order for the injection characteristics to be monitored.udIt was established that the engine requires more fuel when running on DME than onuddiesel in order to obtain the same power output. This is because DME has a lowerudheating value as well as density than diesel. DME CO2 emissions were higher thanuddiesel, while DME CO emissions were lower than diesel. The NOx emissions for DMEudwere higher than diesel at lower engine speeds, and then lower than diesel at higherudengine speeds. It is suspected that the DME emissions are negatively affected by laterudinjection of DME than diesel injection as well as longer duration of injection for DME thanudfor diesel as this may result in incomplete combustion of fuel.